The snow and the ice-covered Arctic is the world’s refrigerator and home to a plethora of wildlife and native tribes. The ice and snow reflect the heat back into the atmosphere and hence balance out the different parts of the world that absorb higher temperatures. However, climate change and global warming have led to ice melting. Less ice leads to heat being reflected less, thus leading to intense heat waves all over the world. Climate change and its effects are often first felt by those who do nothing to contribute to it, like the native communities and the animal kingdom. Here, I have explored the impact of climate change on marine life in the Arctic region.
Polar bears depend on the sea ice to hunt ice-living seals. They make use of the ice-corridors for moving from one area to another. During winter, the pregnant females build their dens in areas with thick snow, covered by sea ice. When the mothers emerge from their dens with the cubs in the spring season, they haven’t eaten for around five to seven months. Their entire seal hunting and feeding process are vital for the family’s survival and it depends on the condition of the spring ice. Hence, any change in the extent and stability of ice is of critical importance. Any projected decline in the sea ice is pretty likely to have alarming consequences on the polar bear and its survival.
The earliest impacts of global warming are expected to happen at the southern limits of where the polar bears are distributed. This included James and Hudson Bays in Canada. In fact, such devastating changes have already been recorded in the past few years. In the Hudson Bay area, the number of adult polar bears has declined significantly over the last two decades. So have the number of healthy live births and the survival of the cubs during their first year. Between the years 1981 and 1998, the adult polar bears in the Hudson Bay area suffered at least a 15% decline in both their average weight and the number of cubs that were born.
The late formation of the sea ice in the autumn season and the early break-up and melting during spring is disastrous for the female polar bears. The female polar bears have to take a longer annual fasting period, which directly affects their reproductive success as it is linked to their fat stores. Females in unhealthy conditions end up having smaller litters. Moreover, the smaller cubs also have a lower survival rate. The number of bear deaths is likely to increase directly as a result of climate change. For instance, the increase in the frequency and intensity of rain during the spring season has been causing the dens to collapse. It is needless to say that females and cubs are killed in the process. Also, the untimely breaking up of spring sea ice separates the traditional den sites from the usual spring feeding areas. The young cubs are not at all capable of swimming long distances from their dens to the feeding areas.
If there is a loss of summer sea-ice cover, then polar bears are most unlikely to survive as a collective species. According to some climate models, this is likely to happen by the end of this century. The only option that the polar bears have is to adapt to a more land-based lifestyle during the summer. But even this poses a myriad of risks, like increased interactions with humans that would further threaten their survival, competition and the risk of hybridisation with grizzly and brown bears. Needless to say, if the polar bears do not survive as a species, then it will have a significant and damaging effect on the ecosystems they occupy currently.
Ice-dependent seals, which include the ribbon seal, ringed seal and bearded seal, are a species particularly susceptible to the increased reductions in the arctic sea ice. This is because they have their little ones and nurse them on the ice, which serves as a resting platform for them. The edge of the ice and the area underneath the ice also serve as foraging grounds for the seals. Out of the different species of seals, ringed seals are most likely to take the biggest hit, since all aspects of their lives depend on the sea ice. They need a sufficient amount of snow to construct their lairs. Moreover, the sea ice must be stable enough during the spring season for the successful rearing of their young. The early breaking up of the ice could possibly result in the premature separation of mothers and their pups, which leads to a higher mortality rate of newborns.
It is highly unlikely that the ringed seal will be able to adapt to life on land due to the absence of sea ice in the summer. This is because ringed seals rarely ever come onto land. Hauling themselves on the land even for resting would be a drastic change in the species’ behavioural patterns. Having their little ones on land would mean the newborns are at a much higher risk of being hunted by predators.
Other ice-dependent seals that are at risk due to climate change effects are the spotted seal and the harp seal. The spotted seal’s exclusive breeding ground is at the ice edge of the Bering Sea during spring. As for the harp seal, its life is tightly linked with sea ice all through the year. On the other hand, harbour seals and grey seals are more temperate species. These seals have significantly broad niches which make them less prone to the impact of climate change. Thus, they are more likely to expand their ranges even if the Arctic has less ice coverage.
Seabirds and the ice edge
Climate change has a drastic effect on some seabirds, like little auks and ivory gulls. The decline in the sea ice means significant changes to the communities they live in. For the most part of its life, the ivory gull is intimately linked with sea ice. It nests and breeds on rocky cliffs, which helps them protect themselves from prowling predators. The ivory gulls also fly to the nearby sea ice for fishing through the ice cracks and scavenge around the top of the ice. Due to climate change, the sea ice edge retreats further away from the birds’ suitable coastal nesting sites. This has led to a serious decline in the ivory gulls’ population. In Canada alone, there has been an estimated 90% reduction over the past two decades.
The walrus and the ice edge
In the Arctic region, the ice edge is both the most productive and vulnerable area to climate change. The areas nearest to the coasts on the continental shelves are the most productive. As sea ice drifts further away from the shorelines, one of the marine animals to bear the negative impacts is the walrus. For the walrus, the edge of the ice serves as an ideal ground for resting and feeding. This is because these marine animals are bottom feeders that feed on clams and other kinds of shellfish found on the continental shelves. As the ice edge moves away from the shelves towards the deeper areas, there will be no clams.
Ice algae and the related food web
Much like its effect on larger mammals, the enormous reduction in the multilayer ice of the Arctic Ocean will disrupt the functioning of microscopic life forms. These tiny creatures’ survival is extensively linked with ice. Studies done in the Beaufort Sea show that ice algae, which lie at the bottom of the marine food web, maybe the organism that has been most profoundly affected by global warming over the past few decades. Studies show that due to the melting of ice, most of the larger marine algae beneath the ice died between the 1970s and 1990s. These have been replaced by another, less productive algae species which is usually associated with freshwater. This is likely due to the fact that the melting of the ice has led to the formation of a thick layer of freshwater below the ice that remains.
The areas that are most susceptible to such changes are the Hudson Bay and the Bering Sea. As rising temperatures continue to warm the Arctic, the sea ice will melt at a quicker rate and drift towards the deep ocean of the central Arctic.
Freshwater fish like the Arctic char, broad whitefish and Arctic cisco are northern freshwater fish. Climate change and temperature rise mean a shift in the southern species to the north, where they compete for resources. Rising temperatures force the cold-water species to move northward in search of suitable spawning grounds. As the southern species move northward, they also introduce many new parasites and diseases to which the northern Arctic species aren’t resistant, thus increasing their mortality rate. Such changes are potentially devastating not just for the animal kingdom, but also for the native communities who feed on this fish. The most vulnerable species are often the only fishable species available.
The Arctic char is one of the northern species in the Arctic. Some of their populations reside in lakes where their primary source of food is the midge larvae. Other populations migrate during the summer to the sea where they feed on smaller fish and crustaceans.
Studies on the Arctic char show that rising temperatures increase the respiratory rate of the fish, which leads to an increase in the accumulation of heavy metals in them. Moreover, climate-induced changes often increase the levels of contaminants in the lakes. The reduced ice cover in the lakes leads to an increased merging of water layers. This results in the contaminants staying in the lakes for longer periods of time.
Warmer temperatures severely impact lake trout. Research shows that an increase in the temperature leads to the trout consuming as much as eight times more food than necessary to maintain body temperature. Apart from affecting their health, it is also concerning regarding the availability of food in lakes. In addition, the combination of rising temperatures, longer open-water seasons and an increase in the levels of phosphorus in the water (an effect of permafrost thaws flowing into the lakes) leads to a significant increase in smaller aquatic life forms. Hence, the amount of oxygen consumed increases, thus reducing oxygen concentrations in deeper water where the trout are found. To fight for survival, the trout will be forced to move near the surface of the lake where temperatures are warmest. Hence, the trout is squeezed into a habitat between the surface and the bottom of the lake.
Other animals on land
Other Arctic animal species on land include small herbivores like hares, ground squirrels, lemmings and voles (small rodents), large herbivores like reindeer, moose and musk ox and carnivores like wolverine, weasels, wolves, bears, fox and birds of prey. Changes brought on by climate change have a wide range of effects on the many species mentioned above. When comparing the ecosystem of the arctic region to those in the warmer regions, the arctic region has a lower number of species. These species are directly or indirectly related to each other and when one topples, it affects the other. The displacement of arctic species has significant consequences on the species that depend on them for survival.
Moss, lichens and reindeer
Moss and lichens need a typical Arctic climate to thrive. They are particularly susceptible to a warmer climate. These plants take a place at the base of the food chain and serve as the primary winter food for reindeer and other species. Hence, their decline will have quite an impact on the ecosystem. The decline of reindeer and other herbivores that feed on them will affect the species that hunt them (like wolves and wolverine) and those that scavenge them (like birds and foxes). Since some native communities like the Sami also depend on the reindeer for survival, they too will be affected. Due to the freezing and thawing of ice, a hard crust of ice encapsulates the reindeer’s food. This restricts their foraging and sometimes the plants are killed too. Recent decades have seen an alarming increase in freeze-thaw events.
Voles and lemmings
The rising temperatures have other implications for the smaller Arctic mammals too. Winter is when the voles and lemmings forage and hibernate in the space between the snow and the frozen tundra ground. The snow provides the mammals with critical insulation. Due to rising temperatures and changing weather conditions, the wet snow leads to the collapse of these burrows under the snow. At the same time, the formation of the ice crust also reduces the much needed insulating properties of the snow that are vital for the animals’ survival. The population cycles of voles and lemmings have already collapsed in some of their usually populated areas. Their decline leads to the decline of their predators too, like snowy owls, ermines and weasels. When the lemming population runs low, predators like the arctic fox are forced to switch to other species for food.
Reindeer and caribou
Reindeer and Caribou are extremely important for the lifestyle of those communities who live in the Arctic region. They are a source of food, fuel, shelter, tools and other cultural items. These animals survive on the availability of tundra vegetation and the foraging conditions, particularly during the calving season. Due to climate change, vegetation zones have shifted northward, bringing down the traditional forage grounds for the caribou and reindeer herds. The increasing amount of rainfall and freeze-thaw cycles also lead to drastic results. The decline of reindeer and caribou means the decline of a vital part of the native communities’ lifestyles and culture.
Climate change and global warming have led to the polar ice caps melting at an alarming rate. This means certain death for the species that depend on the ice for their survival. Studies show that if emissions continue to rise unchecked at the present rate, then the Arctic region could be iceless by the summer of 2040. And what happens in the Arctic certainly does not stay confined to the Arctic. The loss of ice has devastating and far-reaching effects all over the world. Without immediate action to secure a safer and better future, the world will continue to suffer the impact of global warming.